Electrically Pumped Photonic Crystal Nanolaser Rib Structure
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Solution Overview
Problem
Optical pumping of nanolasers is difficult to implement and use due to inefficiencies in light source activation and energy transfer.
Innovation Solution
An electrically pumped nanolaser with a rib structure comprising a stack of III-V semiconductor layers forming quantum wells, where the rib has lateral and longitudinal extensions with metallizations to facilitate electrical current flow and reduce electromagnetic wave absorption, allowing for efficient radiative recombination and laser amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If optical pumping is used to activate the nanolaser, then light emission can be achieved, but the implementation becomes difficult and inefficient due to energy transfer losses
Solution Approach 1:
The patent replaces optical pumping (electromagnetic field interaction) with electrical pumping (electrical current injection). By substituting the optical excitation mechanism with direct electrical injection into the quantum wells, the system eliminates the complex optical coupling requirements and energy transfer inefficiencies associated with optical pumping, while achieving efficient carrier injection and radiative recombination
Solution Approach 2:
The patent introduces lateral extensions with metallizations as intermediary structures that facilitate electrical current flow to the quantum wells. These extensions act as mediators between the external electrical contacts and the active region, enabling efficient electrical pumping while the decreased thickness sections minimize electromagnetic wave absorption and optimize the pumping efficiency
2Power
If the rib structure is used to confine optical modes, then laser amplification is achieved, but electromagnetic wave absorption increases
Solution Approach 1:
The patent applies local quality by varying the thickness of the rib structure along its length. The main rib portion maintains sufficient thickness for optical mode confinement and laser amplification, while the lateral extensions have decreased thickness specifically in the regions where electromagnetic wave absorption would be problematic. This localized thickness variation optimizes both optical confinement and minimizes absorption losses in different regions of the structure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient laser amplification and light emission by overcoming the challenges of optical pumping, improving the optical quality and reducing absorption, thus enhancing the nanolaser's performance.
Implementation Method 1
enables efficient laser amplification and light emission by overcoming the challenges of optical pumping
Implementation Method 2
a laser of submicrometer dimensions, or nanolaser, having its light source formed from an electrically pumped direct bandgap semiconductor
Data Source
AI summary
A semiconductor nanolaser includes a rib formed by a stack of layers, in which stack central layers (33, 34, 35) forming an assembly of quantum wells are placed between a lower layer (32) of a first conductivity type and an upper layer (36) of a second conductivity type. Holes (42) are drilled right through the thickness of the rib, wherein the lower layer includes first extensions (38, 40) that extend laterally on either side of the rib, and that are coated with first metallizations (42, 44) that are located a distance away from the rib. The stack includes second extensions (45, 46) that extend longitudinally beyond said rib, and that are coated with second metallizations (47, 48).